1. Field of the Invention
The present invention relates to an electronic component testing apparatus for testing a variety of electronic components, such as semiconductor integrated circuit devices (hereinafter referred to as an xe2x80x9cICxe2x80x9d or xe2x80x9cICsxe2x80x9d), a tray transfer arm used therefor and a tray transfer method. More particularly, the invention relates to a general purpose tray transfer arm able to maintain stability in holding electronic components regardless of kinds of customer trays, electronic component testing apparatus and a tray transfer method.
2. Description of the Related Art
An electronic component testing apparatus called a xe2x80x9chandlerxe2x80x9d conveys a large number of ICs held on a tray to the inside of a testing apparatus where the ICs are made to electrically contact a test head, then the IC testing unit is made to perform the test. When the test is ended, the ICs are conveyed out from the test head and reloaded on trays in accordance with the results of the tests so as to classify them into categories of good ICs and defective ones.
In a handler of the related art, the trays for holding the DUTs (Devices under test) to be tested or the tested DUTs (hereinafter referred to the xe2x80x9ccustomer traysxe2x80x9d) and the trays conveyed inside the Electronic component testing apparatus (hereinafter referred to as the xe2x80x9ctest traysxe2x80x9d) are different, therefore, the ICs are switched between the customer trays and the test trays before and after the test.
When switching the tested ICs from the test trays to the customer trays, empty customer trays are prepared for the number of categories of good ICs and defective ones, etc., to which the tested ICs are reloaded from the test trays. When the customer trays are filled up, it is necessary to convey the reloaded ICs to prepare new empty customer trays. Thus, a transfer apparatus called a tray transfer arm is provided in the electronic component testing apparatus.
In the tray transfer arms of the related art, as shown in FIG. 12, a customer tray KST loaded with a large number of ICs to be tested is held beneath a tray magazine plate 34. The magazine plate 34 moves in the X, Y and Z direction and thereby, the customer tray KST is transferred to a desired position.
The above test tray is regarded to be a part exclusively for the handler, while the customer tray KST varies in the shape, particularly, the illustrated thickness H (substantially, H1) and the depth D of a pocket KST1 for carrying. ICs to be tested in accordance with kinds of the customer tray KST.
Accordingly, when preparing the tray transfer arm of the handler, it has been a general way to prepare it to be fit to a customer tray having the thickest thickness H, or to switch a hook 40 for holding the tray transfer arm in accordance with kinds of the customer tray.
If the tray transfer arm is made to be fit to a shape of the customer tray having the thickest thickness H, however, the pocket KST1 is too deep as shown in FIG. 12 when holding a customer tray having thinner thickness H, consequently, a space S between the IC to be tested and the bottom surface of the magazine plate 34 becomes large and the IC to be tested is liable to be out of its position on the pocket KST1 during transferring of the customer tray.
Also, there has been a disadvantage that switching the holding hook 40 to an exclusive one in accordance with the kinds of the customer trays KST brings extremely burdensome works and requires a long time for the arrangements.
It is an object of the present invention to provide a tray transfer arm, an electronic component testing apparatus and a tray transfer method which is fully general purpose and able to maintain stability in holding electronic components to be tested regardless of kinds of customer trays.
(1-1) According to the first aspect of the present invention, there is provided a tray transfer arm for holding and transferring a tray having a pocket for loading an electronic component therein, comprising a cover plate for covering an opening surface of the pocket.
In the present invention, it is possible to cover with the cover plate the opening surface of the pocket regardless of kinds of a tray when the tray transfer arm holds and transfer the tray. As a result, the electronic components to be tested become stable without jumping out from their correctly held positions and a high speed transfer becomes attainable and disadvantages, such as a pick-up mistake in the next process, can be prevented beforehand.
The cover plate according to the present invention is not particularly limited. It also includes the tray itself other than exclusive plates. Namely, the tray can be used also as a cover plate.
(1-2) In the above invention, the position of attaching the cover plate is not particularly limited. It can be attached to the respective trays and also to the tray transfer arm. The jumping out of the DUTs from the electronic component magazine easily occurs mainly during transferring at a high speed, which can be prevented simply by attaching the cover plate to the tray transfer arm.
(1-3) In the above invention, the cover plate may be provided exclusively in accordance with the shapes, etc. of the respective trays, and more preferably, the cover plate is provided movably in the vertical direction with respect to the opening surface of the tray. By doing so, one cover plate can be widely used for the trays having different shapes, such as the thickness, etc., as well. Namely, in providing a cover plate to the tray transfer arm, by giving a room (space) in the vertical direction with respect to the opening surface, the cover plate covers by contacting with the opening surface of the tray due to its own wight both when holding a thick tray and a thin tray. Accordingly, it can be used widely to different kinds of trays as far as the room permits.
(1-4) As explained above, the cover plate according to the present invention can be an exclusive part in accordance with kinds of the trays. In this case, although it is not particularly limited, it is preferable that the cover plate is provided removably to the tray transfer arm and forms a projection portion projecting toward the electronic component pocket of the tray.
In this way, even in the case of using exclusive parts in accordance with kinds of the tray, only the cover plate is parts which should be switched. Thus, comparing with the case of switching the holding hook, time for arrangements and increase in cost can be suppressed. Also, in the case of using exclusive parts, the projection portion in accordance with the electronic component to be tested can be formed on the cover plate, and it becomes possible to attain the state where stability of the electronic component to be tested can be maintained most.
(1-5) Furthermore, in the above invention, the cover plate is not necessarily a separate part. It may be the tray magazine plate itself constituting the tray transfer arm. In this case, it is preferable that, along with holding the tray, a hook mechanism for pressing the tray in the direction toward the tray magazine plate is provided.
By doing so, the opening surface of trays having different shapes, such as the thickness, etc., can be pressed to contact with the tray magazine plate, and the electronic components to be tested become stabilized without jumping out from the correctly held position. Therefore, a high speed transfer becomes possible and disadvantages, such as a pick-up mistake, etc. in the next process, can be prevented beforehand.
Also, by forming on the tray magazine plate a projection portion projecting toward the electronic component pocket of the tray, stability of the loaded electronic components to be tested increases furthermore.
(2) According to the second aspect of the present invention, there is provided an electronic component testing apparatus, comprising a tray magazine for carrying therein a tray having a pocket for loading an electronic component to be tested therein and a tray transfer arm for transferring the tray carried in the tray magazine to a loader section, wherein the tray transfer arm comprises a cover plate for covering an opening surface of the pocket.
Also, there is provided an electronic component testing apparatus, comprising a tray magazine for carrying therein a tray having a pocket for loading an electronic component therein, and a tray transfer arm for transferring a tray loaded with post-test electronic components at an unloader section to said tray magazine, wherein the tray transfer arm comprises a cover plate for covering an opening surface of the pocket.
(3) According to the third aspect of the present invention, there is provided a tray transfer method comprising a step for transferring a tray loaded with an electronic component to be tested in a pocket thereof, wherein the tray is transferred in a state that at least an opening surface of the pocket is covered.
In the present invention, a tray is transferred in a state that at least an opening surface of the electronic component pocket is covered when transferring the tray loaded with electronic components in the pocket wherein one primary surface has the opening, therefore, it is possible to prevent the electronic components from jumping. As a result, the electronic components are stabilized without jumping out of the correct held position, so that a high speed transfer becomes possible and disadvantages, such as a pick-up mistake, etc. in the next process, can be prevented beforehand.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.